SB Chevy Intake Gaskets Medium Race Port

The FEL-PRO SB Chevy Intake Gaskets Medium Race Port (MPN 1266) is a precision-engineered intake manifold gasket kit designed for small block Chevrolet engine builders and high-performance mechanics who demand accurate port alignment and reliable sealing under aggressive boost and high-RPM conditions. This gasket set addresses the critical interface between intake manifold and cylinder head, where even minor leaks can compromise fuel mixture quality, reduce throttle response, and create vacuum leaks that defeat tuning efforts. Whether you're assembling a street performance engine or preparing for track duty, proper intake gasket selection is fundamental to engine reliability and consistent power delivery.

Engineered with a 0.12-inch composite construction and medium race port geometry, these gaskets provide superior sealing across rectangular port dimensions of 1.31 by 2.21 inches, optimized for ported cylinder heads and race-prepared manifolds. The composite material resists thermal cycling and chemical attack from coolant and fuel vapors better than traditional cork-rubber designs, while the 0.12-inch thickness maintains proper port alignment without excessive compression that could distort manifold surfaces. Medium race port specifications indicate these gaskets are tailored for moderately ported heads—not fully CNC-ported competition heads, nor stock castings—making them ideal for the sweet spot where most serious street and bracket-race engines operate. The kit format ensures you have all gaskets needed for a complete, matched installation without mixing part numbers across individual purchases.

Small block Chevy enthusiasts preparing engines with intake manifold upgrades, carburetor or EFI conversions, or higher-lift cam swaps benefit most from these gaskets, as each of these modifications increases pressure cycling and thermal stress on the intake seal. Installation requires careful manifold surface preparation—a clean, flat mating surface on both the head and manifold is non-negotiable to achieve the seal integrity these composite gaskets provide. Compatible with all small block Chevy platforms from 262 to 400 cubic inches, these gaskets are a straightforward replacement during any intake work or a worthwhile upgrade during an engine rebuild to eliminate a common source of air leaks and coolant weeping that plagues older, worn assemblies.